Here. There must be an office in Puerto Plata. BushBaby or someone who lives there can give you the details. If not EPS, Business Mail, which is cheaper, those who use it say.
What happens when you sign up with EPS is that you get an EPS number. Any mail sent to that number, even if your name were accidentally ommitted from mail, would go to you at the EPS office where you signed up. You will also be given a PO box in Miami and also a street address, where things weighing more than 2 pounds or anything that must be delivered, such as items carried by UPS should be sent. System works fine. Expensive but cheaper than FedEx. Also very reliable, based on my experience with EPS of more than 15 years.